LDPE, low density polyethylene, low polymerization temperature and pressure. Small molecular weight and low density. The material is soft and has good ductility.

HDPE, high density polyethylene, has high polymerization temperature and pressure. High molecular weight and high density. The material is slightly hard. It is often used to make dishes.

LLDPE, linear low density polyethylene, low polymerization temperature and pressure. The molecular chain has few branches, low density and soft material. High tensile strength and good puncture resistance. It is named because there are few branches in the molecular chain.